Subsea wireline intervention system

ABSTRACT

The present invention is a system for subsea well intervention on a vessel with a boom above a well tree. The system includes a subsea deployment reel, a subsea wireline reel, and an intervention tool. The deployment reel has a deployment wireline with an integrated wire rope tether, a grooved drum, a drum motor means, and a control unit. One end of the deployment reel is fixedly attached to a launch and recovery system on the boom of the vessel, and other end of the deployment reel is attached to the wireline reel. The reels and tool lower into the water from the boom for a set depth above the tree. The subsea wireline reel has deployment wireline, a wireline drum, a wireline drum motor means, and a wireline control unit. The wireline reel detaches downward from the deployment reel, after the two reels have stopped lowering. Then, the intervention tool is delivered a final distance to engage the subsea tree.

RELATED U.S. APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO MICROFICHE APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system for downhole well intervention. More particularly, the present invention relates to a submersible system to deliver intervention tools to a subsea tree. Additionally, the present invention also relates to a method of using a subsea wireline lubricator system.

2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98

Subsea production systems are used to explore, drill and harvest oil and gas field under the ocean floor. Subsea production systems sometimes require drilling of the wells from more than one location, and water and depth factors further determine the establishment of the oil and gas field. Thus, special equipment is required to develop subsea oil and gas fields. Equipment for subsea production systems are constructed with considerations for withstanding extreme conditions, being economically cost-effective, and safe guarding the environment. Even the activity of deploying this equipment requires specialized and expensive vessels. For example, diving devices and robotic devices are used for varying water depths. Maintenance for repair and intervention on the ocean floor is usually very economically costly. The locations are remote, the equipment itself is difficult to transport and to deploy, and the expense of intervention can risk economic failure of an entire subsea production system.

In subsea oil and gas oil and gas production, the tree is an ocean floor assembly of valves, spools, and fittings to control the flow into or out of the well. The tree also covers additional structures, including chemical injection points, well intervention means, pressure relief means, and tree and well monitoring points. Maintenance of the subsea production system relies upon communication with the tree, and well interventions include using tools to interact with the tree.

Typical systems deliver intervention tools by lowering these tools from a crane on a vessel above the subsea tree. A remote operated vehicle (ROV) follows the deployment to the subsea tree and uses the tools underwater to perform repair and intervention tasks, such as controlling flow, surveillance, removing contaminants, and checking plugs and valves on the tree. Prior art systems have been located on the costly drilling rigs themselves and have necessitated specialized well intervention vessels for the specialized equipment in order to reach areas away from the actual rigs. Other prior art systems have adapted smaller vessels for the delivery and deployment of the intervention system.

In the past, various patents have been issued in the field of intervention systems, relating to subsea trees. For example, U.S. Pat. No. 6,488,093, issued on Dec. 3, 2002 to Moss, discloses a well intervention system with a subsea deployed wire line, conventional wire-line, coil tubing, or reeled pipe unit landed on an existing subsea tree. The system delivers a plurality of tools for use by an ROV at the subsea tree without a riser conduit for switching each tool. The intervention system is mounted on a small boat equipped with a crane. In a related variation, U.S. Pat. No. 6,659,180, issued on Dec. 9, 2003 to Moss, teaches a method for connecting the intervention system to the subsea tree such that a carousel of tools is provided for the ROV to make a variety of repairs and interventions from a single mounted location on the tree.

U.S. Pat. No. 4,673,041, issued on Jun. 16, 1987 to Turner et al. teaches a connector for a well servicing system. The remotely operable connector has releasably connectable male and female members. The male member sealingly engages the female member on connection. The female member houses radially moveable dogs which may be locked in connecting engagement in a groove on the male connector by a lock sleeve longitudinally moveable over the dogs. The sleeve, which is biased to dogs locked position, moves to dogs unlocked position in response to pressure applied to a first inlet and may be retained in dogs locked position by continued application of pressure to a second inlet. The female connector houses a pressure lock which prevents movement of the lock sleeve from locked position on application of pressure to the first inlet, if there is pressure in the connector bore. The connector is unlocked for disconnect when there is no pressure in the connector bore and pressure is applied through the first inlet, moving the sleeve to dogs unlocked position. This connector is particularly useful in a disclosed underwater well wireline servicing system, as a wellhead connector or lubricator section connector. The well servicing system provides wireline well servicing of underwater wells without pollution of surrounding water and for emergency disconnect from the underwater wellhead for quick floating service vessel removal.

U.S. Pat. No. 6,612,369, issued on Sep. 2, 2003 to Rocha et al., describes an subsea umbilical termination assembly and launching system. The subseaumbilical termination assembly includes a lift point, a guide surrounding a connector attached to the lift point, a housing with a mandrel for engaging the connector and at least one interface, numerous flying leads connected to the housing, a base for the housing, and an emergency quick disconnect connected to the mandrel. The disconnect has a hydraulic connector that engages hydraulic pistons that can then disengage numerous locking dogs enabling the hydraulic connector to disengage from the UTA. The interface in the housing connects to an electrical umbilical, a fiber optic cable, or hydraulic umbilical.

U.S. Pat. No. 7,036,598, issued on May 2, 2006 to Skjaerseth et al., teaches an intervention module for a well. The intervention module is preferably in a pressurized subsea well with a wellhead disposed on a water floor. The intervention module is provided with necessary equipment to replace, under water, intervention tools and thereby perform several well intervention operations in one run, without the supply of equipment from a surface vessel. The module is lowered from a surface vessel and placed on the wellhead. The intervention module is connected to the surface vessel through a connecting line/hose or a wireless connection which communicates, as a minimum, necessary control and feed-back signals. The module is provided with a rotatable tool magazine arranged with several storage pipes for intervention tools, the relevant storage pipe being rotatable into a position immediately above the well bore of the well, after which the intervention tool is connected to a supply string, whereas the storage pipe is connected in a pressure-sealing manner to the well bore below and a pressure safety device above, through which the supply string is passed, so that the intervention tool may be inserted safely into the well.

U.S. Patent Publication No. 2003/0178200, published on Sep. 25, 2003 to Fox et al., describes a subsea intervention system. The subsea intervention system includes a BOP module and a CT module. A tool positioning system is used for positioning a selected subsea tool stored within a rack with a tool axis in line with the BOP axis, while a marinized coiled string injector is moved by the positioning system to an inactive position. Power to the subsea electric motors is supplied by an electrical line umbilical extending from the surface for powering the pumps, with the hydraulic system controlled by a power control unit. The injector includes a pressure compensator roller bearing and a pressure compensated drive system case.

U.S. Pat. No. 6,763,889, issued on Jul. 20, 2004 to Rytlewski et al., teaches a method and system of subsea intervention. The method and system comprises lowering one or more assemblies of intervention equipment into the sea. Underwater marine units (such as remote operated vehicles or small submarines) are employed to connect the assemblies to each other and to the subsea wellhead equipment. The subsea wellhead equipment includes a carrier line spool (e.g., coiled tubing spool, wireline spool, slickline spool) and equipment to inject a carrier line from the carrier line spool into the subsea well. The carrier line spool can be located underwater, such as on the sea floor or positioned above the subsea wellhead equipment. The carrier line spool can also be located on a sea vessel. Also, to switch tools, a carousel system having multiple chambers containing different types of tools can be used. U.S. Pat. No. 7,264,057, issued on Sep. 4, 2007, also to Rytlewski et al., describes a very similar system and method.

Various patents have issued in the past relating to subsea lubricators. For example, U.S. Pat. No. 3,568,767, issued on Mar. 9, 1971 to Weiss, describes a telescoping wireline lubricator. The telescoping wireline lubricator has first and second telescopically extendable tubular sections so that the lubricator is especially adapted for conducting wireline operations in a closely confined area such as an underwater wellhead installation.

U.S. Pat. No. 6,609,571, issued on Aug. 26, 2003 to Nice et al., teaches a remote subsea lubricator. The lubricator is used for inserting a wireline tool into a subsea well. The lubricator has an elongated tube having an axial passage formed therethrough for receiving the wireline tool. The remote subsea lubricator is lowered beneath the surface of the sea for connection to a subsea well. Contained within the lubricator is the wireline tool. Once connected to the subsea well, the wireline tool is released from the lubricator into the well. The lubricator enables the wireline tool to enter and exit the well without sea water entering the well.

Problems remain for the deployment of well intervention systems from vessels of the prior art. In particular, any vessel, whether a specialized well intervention vessel or a smaller boat with a crane, must compensate for the influence of ocean waves. Referring to FIG. 1, the well intervention systems 101 mounted on large drilling rigs 102 do not encounter as much of this heave problem due to their size, but the enormous expense of an entire rig eliminates the feasability of such rigs for every needed well intervention. The small boats 202 with auxiliary cranes 203 of other prior art intervention systems 201 have failed to account for the adverse conditions at the sea surface. Deployment and steady connection of the well intervention system on the ocean floor cannot be maintained adequately by the prior art systems 101 and 201. The lack of stability or requirement for cost-prohibitive equipment show that the prior art fails to address the needs of the industry.

It is an object of the present invention to provide a system for subsea downhole well intervention.

It is an object of the present invention to provide a system for well intervention without a rig and/or without risers.

It is another object of the present invention to provide a system for subsea well intervention with heave compensation.

It is yet another object of the present invention to provide a system with staged deployment of a drum reel and a wireline reel.

It is still another object of the present invention to provide a system for subsea well intervention deployed from a small vessel.

It is another object of the present invention to provide a cost-efficient system for deployment of an intervention system.

These and other objects and advantages of the present invention will become apparent from a reading of the attached specification.

BRIEF SUMMARY OF THE INVENTION

The present invention is a system for subsea well intervention on a vessel with a boom above a well tree. The system includes a subsea deployment reel, a subsea wireline reel, and an intervention tool. The subsea deployment reel includes a deployment wireline with an integrated wire rope tether, a grooved drum, a drum motor means, and a control unit. The subsea wireline reel has wireline, a wireline drum, a wireline drum motor means, and a wireline control unit. The deployment reel has one end attached to a launch and recovery system (LARS) through the boom on the vessel, and the other end of the deployment reel attaches to the wireline reel. The wireline reel is detachable downward from the deployment reel. The intervention tool is attached to the wireline reel and has a connector so as to engage the well tree. Each of the reels can be contained in housings or cages to dispense the wireline. The wireline of the LARS and the deployment wireline between the deployment reel and wireline reel can be formed with available technology, including but not limited to steel wire rope, fiber optics, and electrical-hydraulic umbilical.

The intervention tool is typically a lubricator, having a pipe with internal grease seal-pack-off assemblies and a stinger, a remote operated vehicle (ROV) function panel, and a lubricator control. The function panel allows an ROV to control the wireline drum motor means, locking switch for the connector, and a grease injector pump at the subsea location. The ROV makes the connection between the intervention tool and the well tree. The intervention tool connects to the well tree by male-female engagement, a connector receptacle of the subsea tree being female and the stinger of the tool being male.

The method for subsea well intervention from a vessel with a boom above a well tree enables the intervention tool to work on the well tree, including injection of lubricant, monitoring, checking valves, etc. The method includes mounting a subsea deployment reel, a subsea wireline reel, and an intervention tool on the boom of the vessel, the subsea deployment reel and the subsea wireline reel being removably attached to each other. The reels and tool are lowered by release of wireline from any prior art launch and recovery system (LARS) until the reels and tool reach a predetermined depth and distance above the well tree. The deployment reel separates from the subsea wireline reel and the intervention tool, the wireline reel detaching from the subsea deployment reel. Thus, the final lowering to reach the well tree is by release of wireline between the deployment reel and the subsea wireline reel. The intervention tool connects to the well tree before activation of the intervention tool.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic view of the prior art systems for subsea well intervention.

FIG. 2 is a schematic view of the system for subsea well intervention of the present invention.

FIG. 3 is another schematic view of the system of the present invention, showing the detached wireline reel and intervention tool.

FIG. 4 and FIG. 5 are partial isolated schematic views of the wireline reel and intervention tool of the present invention.

FIG. 6 is a schematic view of the male-female connection of the stinger of the intervention tool of the present invention and the well tree.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 2 and 3, there is a system 10 for subsea well intervention on a vessel with a boom 14 above a well tree 16. The system includes a subsea deployment reel 18, a subsea wireline reel 20, and a subsea intervention tool 22. The subsea deployment reel 18, a subsea wireline reel 20, and an intervention tool 22 are all mounted on the boom 14 of the vessel. The reels 18, 20 and the tool 22 are lowered by a launch and recovery system (LARS) on the boom 14 until reaching a set depth and distance above the well tree 16. Next, the subsea deployment reel 18 and the subsea wireline reel 20 detach from one another. The subsea wireline reel 20 and the intervention tool 22 continue the descent to the well tree 16. The intervention tool 22 connects to the well tree 16. A remote operated vehicle (ROV) 24 guides and activates the tool 22 on the well tree 16.

The subsea deployment reel 18 is comprised of a deployment wireline 26 with an integrated wire rope tether, a grooved drum 28, a drum motor means, and a control unit. One end of the deployment reel 18 is fixedly attached to the LARS on boom 14 of the vessel, while the other end is attached to the wireline reel 20. The integrated wire rope tether spools onto the grooved drum 28. Also, the deployment wireline 26, grooved drum 28, drum motor means and control unit can be housed in a cage 12 with a lower capture ring. The cage 12 can have optional lighting means, closed circuit television monitoring, and crash guards. The drum motor means is typically electrical-hydraulic. The deployment reel 18 can be attached to the boom 14 of the vessel by a hydraulic U-boom with an integrated control tether, sheave, and a skid frame. The deployment wireline 26 can be formed by known means of a launch and recovery system, including but not limited to steel wire rope, an umbilical, fiber optics or others.

The subsea wireline reel 20 is comprised of deployment wireline 26, a wireline drum 32, a wireline drum motor means, and a wireline control unit. The subsea wireline reel 20 is detachable downward from the subsea deployment reel 18. Similar to the structures of the deployment reel 18, the deployment wireline 26, the wireline drum 32, the wireline drum motor means, and the wireline control unit can be contained in a cage or housing 34. This housing 34 can also be equipped with a lighting means, closed circuit television monitoring, a logging meter, and crash guards, and the wireline drum motor means is also typically electrical-hydraulic. Additionally, the housing has a tether break away.

FIGS. 4 and 5 show more details of the subsea wireline reel 20. FIG. 4 shows the housing 34 with the lighting means 36, closed circuit television monitoring 38, and a logging meter 40. The motor means 48 are illustrated within the housing 34 as well. The tether break away 44 is located on the top of the housing 34, allowing for safe release of the system 10 if seas become too rough and heave becomes to much. The present invention reduces risk to the well tree by reducing the heave and accompanying stress on the well tree. These accessories of the subsea wireline reel 20 provide extra controls and monitoring during the deployment of the system 10 to the well tree 16.

The subsea intervention tool 22 is shown with more details in FIG. 6. The intervention tool 22 is attached to the subsea wireline reel 20 and has a connector 50 so as to engage the well tree 16. In a particular embodiment, the intervention tool 22 engages in a male-female connection with the well tree 16. A connector receptacle 52 of the subsea tree 16 can be a flower pot-bucket type with mechanical locking and establishes the male-female connection with the stinger 54 of the tool 22 as male and the receptacle 52 as female. As an example of an intervention tool 22, such as a lubricator, the tool 22 can be comprised of a pipe 56 with internal grease seal-pack-off assemblies and a stinger 54, an ROV function panel 42 (as also shown in FIGS. 4 and 5), and a lubricator control means. The stinger 54 can be a hydraulic connector to engage the subsea tree 16, and the function panel 42 controls the wireline drum motor means, locking switch for the connector, and a grease injector pump. The lubricator control means can be mechanical-hydraulic. The tool trap accessory 58 is shown in FIG. 6 for fixedly locking the intervention tool in place within the receptacle 52 of the well tree 16.

The method for subsea well intervention from a vessel using the present invention 10 includes mounting a subsea deployment reel 18, a subsea wireline reel 20, and an intervention tool 22 on the boom 14 of the vessel; lowering the reels 18, 20 and tool 22 by a launch and recovery system on the boom 14 until the reels 18, 20 and tool 22 reach a set depth and distance above the well tree 16; releasing the subsea wireline reel 20 and the intervention tool 22 from the subsea deployment reel 18, the wireline reel 20 detaching from the subsea deployment reel 18; further lowering the subsea wireline reel 20 and the intervention tool 22 by release of deployment wireline 26 until the intervention tool 22 reaches the well tree 16; and connecting the intervention tool 22 to the well tree 16. The subsea deployment reel and said subsea wireline reel are removably attached.

The step of connecting the intervention tool 22 includes forming a male-female assembly between a connector receptacle 52 of the subsea tree 16 and a stinger 54 of the intervention tool 22 as male. The connector receptacle 52 is the female portion, being a flower pot-bucket type with mechanical locking at the bearing surface 60 of the stinger 54 and bearing surface 62 of the connector receptacle. Such a connection is locked for a sealed relationship between the tool 22 and the well tree 16.

In practice, the step of connecting the intervention tool requires the use of a remote operated vehicle (ROV) 24 to engage and connect the intervention tool 22 and the well tree 16. The locking connection between the intervention tool 22 and the well tree 16 is set by the ROV 24, which also can test the seal integrity of the connection between the intervention tool 22 and the well tree 16.

Once in place and locked, the intervention tool can be activated to perform the required intervention tasks, such as injecting lubricant, flushing the lubricator, monitoring flow, and control of locking the deployment reel 20 or the wireline reel 22. The commands may originate from either a control unit on the surface in the vessel, a control unit in the deployment reel 20, a control unit in the wireline reel 22, or subsea control by the ROV 24. The communication and control units can be set with great flexibility with possible use of umbilical or steel wire and wireless technology.

The present invention provides a unique and innovative system for subsea downhole well intervention. The system can be deployed from a vessel without special equipment and does not require a completely independent rig or a riser from the well tree. Importantly, the present invention is heave compensated by the separation of the deployment reel and the wireline reel. The stresses from the surface to the deployment death are minimized because the wireline is exposed to less stress in the connection to the well tree. Additionally, the well tree is safer because of the elimination of these upward forces on the locked intervention tool. The prior art systems with subsea location of the intervention tool currently do not provide this protection for the subsea production system. Furthermore, the system of the present invention allows for variable control units at the surface and subsea levels for greater adaptability for different situations. The wireline can be plain steel wire rope or more sophisticated umbilicals and fiber optics between the two reels and relative to the wireline of the prior art LARS on the boom of the vessel. The present invention is a cost-effective and novel solution to the problems of excessive costs and risks from environmental conditions. The staged deployment by a drum reel and a wireline reel as claimed allows subsea well intervention deployed from a small vessel in a safe and efficient manner that has not been taught in the field of subsea production.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the described system, along with the steps of the described method, can be made within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents. 

1. A system for subsea well intervention on a vessel with a boom above a well tree, the system comprising: a subsea deployment reel, being comprised of a deployment wireline, an integrated wire rope tether, a grooved drum, a drum motor means, and a control unit, the deployment reel having one end fixedly attached to the boom of the vessel, said integrated wire rope tether being spooled onto said grooved drum; a subsea wireline reel, being comprised of wireline, a wireline drum, a wireline drum motor means, and a wireline control unit, said subsea wireline reel being detachable downward from said subsea deployment reel; and a subsea intervention tool, being attached to said subsea wireline reel, said subsea wireline reel being placed between said subsea deployment reel and said subsea intervention tool, said subsea intervention tool having a connector so as to engage the well tree.
 2. The system for subsea well intervention according to claim 1, wherein said deployment wireline is comprised of steel wire rope, fiber optics, or electrical-hydraulic umbilical.
 3. The system for subsea well intervention according to claim 1, wherein said wireline is comprised of steel wire rope, fiber optics, or electrical-hydraulic umbilical.
 4. The system for subsea well intervention according to claim 1, said deployment wireline, grooved drum, drum motor means and control unit being housed in a cage with a lower capture ring.
 5. The system for subsea well intervention according to claim 4, wherein said cage has a lighting means, closed circuit television monitoring, and crash guards.
 6. The system for subsea well intervention according to claim 4, said drum motor means being electrical-hydraulic.
 7. The system for subsea well intervention according to claim 1, said wireline, the wireline drum, the wireline drum motor means, and the wireline control unit being contained in a housing.
 8. The system for subsea well intervention according to claim 7, wherein said housing has a lighting means, closed circuit television monitoring, and crash guards.
 9. The system for subsea well intervention according to claim 7, said wireline drum motor means being electrical-hydraulic.
 10. The system for subsea well intervention according to claim 7, wherein said housing has a tether break away.
 11. The system for subsea well intervention according to claim 1, wherein said intervention tool is comprised of a lubricator, said lubricator comprising a pipe with internal grease seal-pack-off assemblies and a stinger, an ROV function panel, and a lubricator control means, said stinger being a hydraulic connector to engage the subsea tree, the function panel controlling the wireline drum motor means, locking switch for said connector, and a grease injector pump, said lubricator control means being mechanical-hydraulic.
 12. The system for subsea well intervention according to claim 11, further comprising: a tool trap housed in said lubricator.
 13. The system for subsea well intervention according to claim 11, said intervention tool being engageable with a connector receptacle of the subsea tree, said connector receptacle being a flower pot-bucket type with mechanical locking and being in male-female connection with the stinger of the lubricator as male.
 14. The system for subsea well intervention according to claim 1, said deployment reel being attached to the boom of the vessel by a launch and recovery system, being comprised of an integrated control tether, sheave, and a skid frame.
 15. A method for subsea well intervention from a vessel with a boom above a well tree, said method comprising the steps of: mounting a subsea deployment reel, a subsea wireline reel, and an intervention tool on the boom of the vessel, said subsea deployment reel and said subsea wireline reel being removable attached to each other; lowering the reels and tool by a launch and recovery system on said boom of said vessel until the reels and tool reach a set depth and distance above the well tree; releasing said subsea wireline reel and said intervention tool from said subsea deployment reel, the wireline reel detaching from said subsea deployment reel; and connecting said intervention tool to the well tree.
 16. The method for subsea well intervention according to claim 15, said step of connecting said intervention tool comprising: forming a male-female assembly between a connector receptacle of the subsea tree and a stinger of the intervention tool as male, said connector receptacle being a flower pot-bucket type with mechanical locking; and locking the male-female assembly.
 17. The method for subsea well intervention according to claim 15, said step of connecting said intervention tool comprising: using a remote operated vehicle to engage and connect the intervention tool and the well tree; locking connection between the intervention tool and the well tree by the remote operated vehicle; and testing seal integrity of the connection between the intervention tool and the well tree.
 18. The method for subsea well intervention according to claim 15, further comprising the step of: activating the intervention tool through the wireline reel by deployment through a blow-out preventer stack by a control unit on the vessel, on the deployment reel or on the wireline reel.
 19. The method for subsea well intervention according to claim 17, further comprising the step of: activating the intervention tool through the wireline reel by deployment through a blow-out preventer stack by an ROV.
 20. The method for subsea well intervention according to claim 15, further comprising the step of: releasing said wireline reel from said deployment reel by an emergency tether when environmental conditions require protection of the subsea tree and vessel. 